The impact of blood type on the mortality of patients with severe abdominal trauma: a multicenter observational study

Few studies have investigated the relationship between blood type and trauma outcomes according to the type of injury. We conducted a retrospective multicenter observational study in twelve emergency hospitals in Japan. Patients with isolated severe abdominal injury (abbreviated injury scale for the abdomen ≥ 3 and that for other organs < 3) that occurred between 2008 and 2018 were divided into four groups according to blood type. The association between blood type and mortality, ventilator-free days (VFD), and total transfusion volume were evaluated using univariate and multivariate regression models. A total of 920 patients were included, and were divided based on their blood type: O, 288 (31%); A, 345 (38%); B, 186 (20%); and AB, 101 (11%). Patients with type O had a higher in-hospital mortality rate than those of other blood types (22% vs. 13%, p < 0.001). This association was observed in multivariate analysis (adjusted odds ratio [95% confidence interval] = 1.48 [1.25-2.26], p = 0.012). Furthermore, type O was associated with significantly higher cause-specific mortalities, fewer VFD, and larger transfusion volumes. Blood type O was associated with significantly higher mortality and larger transfusion volumes in patients with isolated severe abdominal trauma.